Compression resilience and impact resistance of fiber-reinforced sandwich composites

This paper presents an experimental investigation on the compression behavior of fiber-reinforced sandwich composites. In this study, five different types of sandwich composites were prepared with warp knitted spacer fabric as middle layer. Four different types of woven Kevlar fabric structures were used as outer layers (skin) along with one sample of woven basalt fabric. The middle layer used is 100% polyester spacer fabric. Sandwich composites were fabricated using epoxy resin by wet lay-up method under vacuum bagging technique. Compression behavior, ball burst, and knife penetration were tested for all samples. The effect of outer layer of these composites on the mechanical performance was studied using the compression stress-strain curves. It is known that spacers have excellent compression elasticity and cushioning. Maximum knife penetration resistance is obtained with twill weave on surface because of maximum yarn cohesion and resin impregnation. Higher amount of cohesive friction results in higher resistance against penetration of sharp objects like the knife edge. Plain and twill fabrics offer sufficient resistance again ball burst. The yarn deformation allows formation of dome shape after ball impact. Maximum impact resistance in ball burst is obtained for plain weave because of highest level of interyarn binding. The results provide new understanding of knitted spacer fabric-based sandwich composites under compression and impact loading condition.
ball impact, bulging, compression, knife penetration, sandwich composite structures